The company will notify owners, and dealers will replace the electronic flasher unit, free of charge. The recall will begin by mid-June 2014. Mack's number for this recall is SC0379.

The truck maker is recalling another 490 model year 2014-2015 CXU trucks manufactured Feb. 1, 2013, through Jan. 27, 2014 that are equipped with a vertical wet tank, also known as a supply air tank, for the brake system.

In the affected trucks, the pressure relief valve may not have been installed in the tank during manufacturing. Without a pressure relief valve, the air tank could rupture from being over-pressurized, increasing the risk of injury.

Mack will notify owners, and dealers will install a pressure relief valve in the air tank, free of charge. The recall will begin by mid-June 2014. Mack's number for this recall is SC0380.

These vehicles might not conform to Federal Motor Vehicle Safety Standard number 108, "Lamps, Reflective Devices, and Associated Equipment” because the exhaust pipes could be blocking the white reflectors at the rear of the cab. A blocked reflector makes the truck-tractor less visible when operating the vehicle without a trailer in the dark and so increases the risk of a crash.

Mack was scheduled to begin the recall this May. Dealers will inspect the trucks and if the reflectors are blocked, they will add two vertical white reflectors to the rear glass, free of charge. Mack's number for this recall is SC0378.